Lee, M Cho, YW Park, JH Chung, HS Jeong, SY Choi, KW Moon, DH Kim, SY Kim, IS Kwon, IC 2024-01-21T03:39:24Z 2024-01-21T03:39:24Z 2021-09-02 2006-02 0303-402X https://pubs.kist.re.kr/handle/201004/135782 A novel and simple method for size control of self-assembled nanoparticles is suggested in this paper. Polymeric nanoparticles were prepared from amphiphilic chitosan derivatives fluorescein isothiocyanate (FITC)-conjugated glycol chitosans (FGCs). The attachment of hydrophobic FITC onto hydrophilic glycol chitosan induced the amphiphilic conjugate to form self-assembled nanoparticles in aqueous media, depending on degree of substitution. The size of self-assembled nanoparticles was controlled by a novel emulsion/solvent evaporation method. Adding a small amount of an immiscible solvent with water (chloroform) to FGC nanoparticle suspensions in aqueous media followed by ultrasonification and solvent evaporation led to partial dissociation and subsequent reformation of nanoparticles. The evaporation of chloroform facilitated the hydrophobic association, which resulted in more dense and hardened hydrophobic cores. The size of nanoparticles was closely related with the FGC concentration in the emulsion. The mean diameters of self-assembled nanoparticles were 150-500 nm at the FGC concentrations of 0.3-2.5 mg/ml. Higher FGC concentration resulted in larger particles. The polydispersity factors (mu(2)/r(2)) of the reformed nanoparticles were fairly low (0.001-0.094), indicating narrow size distribution. The FGC nanoparticles were stable in phosphate-buffered saline at 37 degrees C up to 20 days. Lactose was a good excipient for maintaining the structural integrity of nanoparticles during freeze-drying. Without lactose, the freeze-dried nanoparticles were not homogeneously redispersed in aqueous media. However, the freeze-dried nanoparticles with lactose were spontaneously redispersed in aqueous milieu with their own sizes. English SPRINGER ACID-MODIFIED CHITOSAN BEARING 5-BETA-CHOLANIC ACID DELIVERY DRUG WATER Size control of self-assembled nanoparticles by an emulsion/solvent evaporation method Article 10.1007/s00396-005-1413-3 1 COLLOID AND POLYMER SCIENCE, v.284, no.5, pp.506 - 512 COLLOID AND POLYMER SCIENCE 284 5 506 512 scie scopus 000234934100007 2-s2.0-31744437037 Chemistry, Physical Polymer Science Chemistry Polymer Science Article ACID-MODIFIED CHITOSAN BEARING 5-BETA-CHOLANIC ACID DELIVERY DRUG WATER nanoparicles size control colloidal stability glycol chitosan fluorescein isothiocyanate lactose